Molecular dynamics study on the formation of dipole layer at high-k/SiO2 interfaces

Abstract

We show that electric dipole layer at Al2O3/SiO2 interface is reproduced by classical molecular dynamics simulation with a simple two-body rigid ion model. The dipole layer was spontaneously formed by the migration of oxygen ions from Al2O3 side to SiO2 side. Built-in potential at the Al2O3/SiO2 is estimated to about 0.35 V, which roughly compares with the experimental value of the flat band voltage shift. Contrary, no significant dipole layer appeared at Y2O3/SiO2 interface. The simulation results are explained in terms of the difference in the magnitude of multipole moments around cations of these oxides.